NIR Dorcy Jr.

Hi,

I have an 780nm 200mW NIR laser diode. It runs using 130mA and 2.4V. I want to house this in a Dorcy Jr. and i was wondering what resistor and silicone diode i should use to lower 300mA to 130mA and 3V to 2.4V. How should i connect it? in series or parallel? I would really appreciate an answer.

Thanks

BTW, here is the data sheet for the NIR laser diode: www.zet.biz/Laser/Data/gh0780ma2c.pdf

Unfortunately the equations to figure this out are prretty inaccurate. Your best bet would be to buy three resistor values (or more) around the area of your calculations, try the higher one first, and measure it with a multimeter. Then change the resistor combinations until you get around your target. The formula is initial voltage-the diode requirements divided by the target current. So 3.3 volts on a fresh cr123 minus 2.4 volts= .9volts so then divide that by .13 and you get roughly 7 ohms resistance. Buy a few different values around this area. This ebay seller allows you to choose 3 values per purchase and you get ten of each value: http://cgi.ebay.com/RESISTORS-1-2-W...ryZ73148QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

Good luck!
P.S. i do not guarantee the accuracy of my calculations, can someone validate this?

Is this about direct drive or direct drive off a boost circuit?

In this case, the current will not be stable, so you'd need to use such resistors, that would prevent the current from going over the maximum safe current even with completelly full batteries and when the diode heats up and becomes more conductive.


What kind of a boost circuit does the Dorcy Jr. have? I doubt it is current regulated. If it was, that would be very good news tho. You could simply bypass some current through a resistor in parallel with the load.


The datasheet doesn't show if this diode has the anode or the cathode at the base. Can you post pics of the diode and some pics of the Dorcy boost circuit?



P.S. Oh, and how many threads do you need to start about the same thing really?

The dorcy is regulated, it puts out 300mA as an output current. But that is way to much to power that diode. And yes, this diode has an anode and cathode at the base, it looks exactly like a 16x DVD diode. I think i should use a 10 ohm resistor or a 15 ohm resistor. Please validate this?

BTW, the resistors are gonna be 1/4 watt

Spyderz20x6 said:

The dorcy is regulated, it puts out 300mA as an output current. But that is way to much to power that diode. And yes, this diode has an anode and cathode at the base, it looks exactly like a 16x DVD diode. I think i should use a 10 ohm resistor or a 15 ohm resistor. Please validate this?

Click to expand...

If you think the dorcy only puts out 300ma your going to be in for a rude awakening. Each flashlight is different and puts out anywhere from 350-400ma. spells instant death for your diodes

Then, i will probably use a 15 ohm resistor

for crying out loud.  so you will shut up and stop asking this question in thousands of stupid threads here is the answere you won't f*ckin work for by studying and reading.  in a dorcy Jr. a 22 ohm resistor will drop the current down to 35ma or thereabouts.  You should use about a 10-15ma resistor in your dorcy to get you 130ma.  Probably closer to 10ma.

Now I certainly hope that you understand that if you want things in life you have to work for them not wait for them to be handed to you on a silver platter. I can see you 10 years from now flipping burgers at mcdonalds or sitting on the side of the street cleaning windows of passing cars with your bottle of windex.

And yes, i do understand i have to work to get things done. But this time, i made an exception.

BTW, i guess you were so caught up in your anger that you didn't notice you said 10ma or 15ma instead of 10 ohms and 15 ohms

Hey Kenom --

Just a friendly little jab

Mike